Node-RED Controller

[pdawcewicz]

Hi Matt.

I'm looking for way to control my DMX decoder using RS485 hat on Rpi. I'd love to control it in Node-RED environment.
Shield's manufacturer supplied a sample python code, sending a simple test string over RS485, and it works, but I'm wandering how can I modify this code, making it send DMX frames. Maybe you could give me some tips how to do it, because unfortunately, I don't know python.

Here is the code which I've simplified a little bit, and original one in the link below.

import serial
import os
import sys
import logging

logging.basicConfig(level=logging.INFO)
libdir = os.path.join(os.path.dirname(os.path.dirname(os.path.realpath(file))), 'lib')
if os.path.exists(libdir):
sys.path.append(libdir)

import RPi.GPIO as GPIO
import time
from waveshare_2_CH_RS485_HAT import config

TXDEN_1 = 27
TXDEN_2 = 22

ser = config.config(dev = "/dev/ttySC0")
data = ''
GPIO.output(TXDEN_1, GPIO.LOW)
ser.Uart_SendString('Waveshare 2-CH RS485 HAT\r\n')
time.sleep(0.005)#Waiting to send
GPIO.output(TXDEN_1, GPIO.HIGH)

https://www.waveshare.com/wiki/2-CH_RS485_HAT

Regards,
Paweł

[MattIPv4]

Hey! it sounds like this is a serial device? If so, the serial controller in the project might be what you want?

https://github.com/MattIPv4/PyDMXControl/blob/master/PyDMXControl/controllers/_SerialController.py

If it isn't a true serial device, you might be able to use that controller as a basis for implementing your own controller that makes the right calls to send each DMX frame

[pdawcewicz]

Hey.
Thanks. That is what I was looking for. I was wandering how to get this >88 usec break and >8 usec idle before sending the pocket, and you are doing it at the very end of the code:

    self.__device.send_break(100e-6)
    sleep(10e-6)
    self.__device.write(data)

It seems I will be able to handle DMX protocol this way, using your python code, but maybe you could give me some ideas how to achieve that in Node-RED, if you have any experience with this environment.

[MattIPv4]

Unfortunately, I'm not familiar with Node-RED, sorry.